The proposed study utilizes the investigator's experience in speech-language pathology and cognitive neuropsychology as well as her training in clinical neurology to identify brain- behavior relationships in hyperacute stroke (within 24 hours of onset), that is, before the opportunity for brain reorganization. The investigation will focus on the characterization and localization of naming disorders and hemispatial neglect. Cognitive testing in the hyperacute period, at 3 days and at 3 months will evaluate the mental representations and processes underlying naming and spatial attention. Areas of hypometabolism, hypoperfusion, and actual infarct associated with specific impairments in these cognitive domains will be identified with magnetic resonance imaging techniques of Perfusion Imaging (MRPI) and Diffusion Weighted Imaging (DWI) and with follow-up conventional MRI. The correlations between acute functional impairments of specific cognitive representations and physiologic or structural lesions will be used to predict the size and site of infarcted or hypoperfused neural tissue from cognitive impairments in hyperacute stroke, and will thus be useful in treatment decisions and prognosis.